1. Technical Field
The disclosure relates to a manufacturing method of a sintered alloy, a sintered-alloy compact, and a sintered alloy.
2. Description of Related Art
There is a case where a sintered alloy with an iron matrix is used for a valve seat and the like of an internal combustion engine. There is also a case where hard particles are contained in a sintered alloy to improve wear resistance. In the case where the hard particles are contained, graphite particles and iron particles are mixed with the hard particles into a powder form and press the mixed powder into a sintered-alloy compact. Thereafter, the sintered-alloy compact is heated and sintered into a sintered alloy.
As a manufacturing method of such a sintered alloy, a manufacturing method of a wear-resistant iron-based sintered alloy has been suggested (for example, see Japanese Patent Application Publication No. 2004-156101 (JP 2004-156101 A)). In the manufacturing method of the wear-resistant iron-based sintered alloy, mixed powder of hard particles, graphite particles, and iron particles is pressed into a sintered-alloy compact. Then, the sintered-alloy compact is sintered while carbons (C) in the graphite particles of this sintered-alloy compact are diffused into the hard particles and the iron particles.
Here, the hard particles contain 20 to 70 mass % of Mo, 0.2 to 3 mass % of C, 1 to 15 mass % of Mn, and the remainder is formed with inevitable impurities and Co. When total mass of the hard particles, the graphite particles, and the iron particles is set as 100 mass %, the mixed powder contains 10 to 60 mass % of the hard particles and 0.2 to 2 mass % of the graphite particles. Because the hard particles are diffused in such a sintered alloy, abrasive wear of the sintered alloy can be suppressed.